Heat dissipation device with a heat pipe

ABSTRACT

A heat dissipation device includes a seat and a base having a first face and a second face opposite to the first face and thermally contacting the seat. A plurality of fins extends from the first face of the base. Two heat pipes are thermally arranged on the second face of the base. Each of the two heat pipes is bent and has a section sandwiched between the base and the seat, and another section thereof stretching along the base from said section to a portion of the base in no attachment with the seat.

FIELD OF THE INVENTION

The present invention relates to heat dissipation devices for use inremoving heat from electronic devices, and more particularly to a heatdissipation device incorporating a heat pipe for improving heatdissipation efficiency of the heat dissipation device.

DESCRIPTION OF RELATED ART

During operation of an electronic device such as a computer centralprocessing unit (CPU), a large amount of heat is often produced. Theheat must be quickly removed from the electronic device to prevent itfrom becoming unstable or being damaged. Typically, a heat dissipationdevice is attached to an outer surface of the electronic device toabsorb heat from the electronic device. The heat absorbed by the heatdissipation device is then dissipated to ambient air.

Conventionally, a heat dissipation device comprises a solid metal baseattached on the electronic device, and a plurality of fins arranged onthe base. The base is intimately attached on the electronic devicethereby absorbing the heat generated by the electronic device. Most ofthe heat accumulated at the base is transferred to the fins and is thendissipated from the fins. However, electronics technology continues toadvance, and increasing amounts of heat are being generated by powerfulstate-of-the-art electronic devices. Many conventional heat dissipationdevices are no longer able to efficiently remove heat from theseelectronic devices.

In order to overcome the disadvantages of the heat dissipation deviceset out above, one type of heat dissipation device used for theelectronic device includes a heat pipe for transferring heat from aposition to another position of the heat dissipation device. The heatpipe is a vacuum-sealed pipe that is filled with a phase changeablefluid, usually being a liquid, such as water, alcohol, acetone and soon, and has an inner wall thereof covered with a capillaryconfiguration. As the electronic device heats up, a hot section which isusually called the evaporating section of the heat pipe and is locatedclose to the electronic device also heats up. The liquid in theevaporating section of the heat pipe evaporates and the resultant vaporreaches a cool section usually called condensing section of the heatpipe and condenses therein. Then the condensed liquid flows to theevaporating section along the capillary configuration of the heat pipe.This evaporating/condensing cycle repeats and since the heat pipetransfers heat so efficiently, the evaporating section is kept at ornear the same temperature as the condensing section of the heat pipe.Correspondingly, the heat-transfer capability of the heat dissipationdevice including the heat pipe is improved greatly.

Typically, a heat dissipation device illustrated as follows is used. Theheat dissipation device comprises a base for absorbing heat from a heatgenerating electronic device, a heat pipe thermally connected to thebase, and a plurality of fins arranged on the base. Generally, the heatpipe is I-shaped. The base defines a groove substantially in the centerthereof receiving the heat pipe therein. In use, the base is in contactwith the electronic device and absorbs heat from the electronic device.The heat in the base is absorbed by the heat pipe, and the heat pipetransfers the heat from the center to other parts of the base. The heatin the base spreads to the fins to be dissipated to ambient air.However, the heat pipe is straight, which results in the thermallycontacting area between the base and the heat pipe being relativelysmall. Consequently, the heat in the center of the base can not betransmitted to other parts of the base rapidly and evenly. The heatgenerated by the electronic device accumulates in the center of the baseand the electronic device. Normal functions and abilities of theelectronic device are adversely affected. Therefore, the heatdissipation device needs to be improved.

What is needed, therefore, is a heat dissipation device which achieves agreater heat-transfer capability and a greater heat dissipationcapability.

SUMMARY OF INVENTION

A heat dissipation device in accordance with a preferred embodiment ofthe present invention comprises a seat for absorbing heat from a heatgenerating electronic device, and a base having a first face and asecond face opposite to the first face and thermally contacting theseat. A plurality of fins integrally extends from the first face of thebase. Two heat pipes are thermally arranged on the second face of thebase. Each of the two heat pipes is bent and has a section sandwichedbetween the second face of base and the seat, and another sectionthereof stretching along the second surface of the base from saidsection to a portion of the base in no attachment with the seat.

Other advantages and novel features of the present invention will becomemore apparent from the following detailed description when taken inconjunction with the accompanying drawings, in which:

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an exploded, isometric view of a heat dissipation device inaccordance with a first embodiment of the present invention;

FIG. 2 is an inverted view of FIG. 1 but without a base;

FIG. 3 is an inverted and assembled view of FIG. 1;

FIG. 4 is an inverted and partially assembled view of a heat dissipationdevice in accordance with a second embodiment of the present invention;

FIG. 5 is an inverted and partially assembled view of a heat dissipationdevice in accordance with a third embodiment of the present invention;and

FIG. 6 is an inverted and partially assembled view of a heat dissipationdevice in accordance with a fourth embodiment of the present invention.

DETAILED DESCRIPTION

Referring to FIGS. 1 and 2, a heat dissipation device according to afirst embodiment of the present invention for dissipating heat generatedby an electronic device (not shown) located on a printed circuit board(not shown) is shown. The heat dissipation device comprises a seat 10, aheat sink 30 on the seat 10, and two heat pipes 50 thermally contactingthe seat 10 and the heat sink 30.

The seat 10 is a substantially rectangular metal plate having greatthermal conductivity, and has a bottom face (not labeled) for contactingwith the electronic device (not shown) and a top face (not labeled)opposite the bottom face. Two parallel grooves 110 each withsemicircular cross section are defined in the top face of the seat 10for receiving the heat pipes 50 therein.

The heat sink 30 comprises a base 31 and a plurality of fins 33 on thebase 31. The base 31 is a substantially rectangular plate and comprisesa top face having the fins 33 integrally extending therefrom and abottom face having a protrusion 34 extending downwardly from a centerportion thereof. The protrusion 34 has a bottom face thereof definingtwo substantially U-shaped grooves 310 therein. The two grooves 310 arejuxtaposed in the bottom face of the base 31 but oriented oppositely toeach other. Each groove 310 comprises a first section 311 and twoparallel second sections 313 substantially perpendicularly extendingfrom two ends of the first section 311, respectively. The first sections311 of the grooves 310 are located adjacent a center of the protrusion34. The second sections 313 of the grooves 310 are located adjacent twoopposite lateral sides of the bottom face of the base 31. The two firstsections 311 of the two grooves 310 are parallel to each other. Thecorresponding second sections 313 of the two grooves 310 extendoppositely in the bottom face of the base 31. A round corner is formedat each joint of the first section 311 and second sections 313 of eachgroove 310.

Each of the two heat pipes 50 is substantially U-shaped and is identicalto the groove 310 of the base 31 in profile. Each heat pipe 50 comprisesa first transferring section 510 and two substantially parallel secondtransferring sections 530 extending from two ends of the firsttransferring section 510. A round corner is formed at each joint of thefirst and second transferring sections 510, 530 of each heat pipe 50.

Referring to FIG. 3, the top face of the seat 10 is thermally combinedto the bottom face of the protrusion 34 of the heat sink 30. Therefore,the grooves 110 of the seat 10 and the first sections 311 of the grooves310 of the base 31 of the heat sink 30 corporately define two parallelchannels (not labeled). The two heat pipes are juxtaposed in the base 31of the heat sink 30. The first transferring sections 510 of the two heatpipes 50 are accommodated in the two channels, respectively. The secondtransferring sections 530 of the two heat pipes 50 extend beyond theseat 10 and are received in the second sections 313 of the grooves 310of the heat sink 30, respectively. Therefore, the two heat pipes 50 arethermally combined to the heat sink 30 side by side but oppositely. Thefirst transferring sections 510 of the two heat pipes 50 are positionedadjacent the center of the bottom face of the base 31 of the heat sink30. The corresponding second transferring sections 530 of the two heatpipes 50 extend oppositely and are positioned near the two oppositelateral sides of the base 31 of the heat sink 30.

In use, the bottom face of the seat 10 contacts the electronic device toabsorb heat from the electronic device. The heat in the seat 10 isabsorbed by the first transferring sections 510 of the heat pipes 50 andthe protrusion 34 of the heat sink 30. And then, part of the heat in theheat pipes 50 and the protrusion 34 directly spreads upward to the fins33, and part of the heat is transferred outwardly to lateral portion ofthe base 31 of the heat sink 30 via the second transferring sections 530of the heat pipes 50. Subsequently, the heat in the fins 33 isdissipated to ambient air.

According to the first embodiment of the present invention, the heatpipes 50 combined to the bottom of the base 31 of the heat sink 30 arecurved to form a U-shape; therefore, the heat pipes 50 and the base 30have a larger thermal contacting area therebetween; the heat in thecenter of the base 31 can be transferred to lateral portions of the base31 rapidly via the second transferring sections of the heat pipes 50 incomparison with the conventional heat dissipation device; therefore, theheat generated by the electronic device is evenly distributed to thebase 31, to thereby be dissipated by the fins 33 rapidly. Thus, theheat-dissipating capability of the present invention is improvedgreatly.

Referring to FIG. 4, a heat dissipation device in accordance with asecond embodiment of the present invention is shown. The heatdissipation device is similar to the heat dissipation device of thefirst embodiment, but the main difference is that each of two heat pipes50 a has one of two second transferring sections 530 a thereof locatedadjacent to a center of a bottom face of a base 31 a of the heat sink30, the other of the two second transferring sections 530 a locatedadjacent to lateral sides of the base 31 a of the heat sink 30. Twofirst transferring sections 510 a of the two heat pipes 50 aresubstantially parallel to each other and are located adjacent to twoopposite lateral sides of the base 31 a. The second transferringsections 530 a of the two heat pipes 50 a are parallel to each other.The base 31 a of the heat sink 30 defines grooves 310 a accommodatingthe heat pipes 50 a therein.

Referring to FIG. 5, a heat dissipation device in accordance with athird embodiment of the present invention is shown. The heat dissipationdevice is similar to the heat dissipation device of the secondembodiment, but the main difference is that one of two heat pipes 50 bof the heat dissipation device has one second transferring section 530 blocated between two second transferring sections 530 b of the other heatpipe 50 b. A base 31 b of the heat sink 30 defines grooves 310 baccommodating the heat pipes 50 b therein.

Referring to FIG. 6, a heat dissipation device in accordance with aforth embodiment of the present invention is shown. The heat dissipationdevice is similar to the heat dissipation device of the thirdembodiment, but the main difference is that two heat pipes 50 c of theheat dissipation device are substantially rectangular without beingclosed up. Each heat pipe 50 c comprises four transferring sections 510c. Each heat pipe 50 c has one transferring section 510 c positionedadjacent a center of a base 31 c, and other three transferring sections510 c positioned adjacent three lateral sides of the base 31 c of theheat sink 30. The transferring section 510 c adjacent the center of thebase 31 c of one heat pipe 50 c is disposed among the four transferringsections 510 c of the other heat pipe 50 c. Therefore, the two heatpipes 50 c are located in the base 31 c taking the format crossingloops.

It is believed that the present invention and its advantages will beunderstood from the foregoing description, and it will be apparent thatvarious changes may be made thereto without departing from the spiritand scope of the invention or sacrificing all of its materialadvantages, the examples hereinbefore described merely being preferredor exemplary embodiments of the invention.

1. A heat dissipation device comprising: a base having a first face anda second face opposite to the first face; a seat attached to the secondface of the base and adapted for absorbing heat from an electronicdevice; a plurality of fins arranged on the first face of the base; anda bent heat pipe comprising a section sandwiched between the seat andthe second face of the base, and another section stretching on thesecond surface of the base from said section to a portion of the base inno attachment with the seat.
 2. The heat dissipation device of claim 1further comprising a heat pipe having a section sandwiched between theseat and the second face of the base, and another section stretching onthe second surface of the base from said section to a portion of thebase in no attachment with the seat.
 3. The heat dissipation device ofclaim 2, wherein each of the heat pipes is generally U-shaped andcomprises a first section and two second sections extending from twoends of the first section.
 4. The heat dissipation device of claim 3,wherein the first sections of the two heat pipes are parallel to eachother and sandwiched between the second face of the base and the seat.5. The heat dissipation device of claim 4, wherein the second sectionsof the two heat pipes extend oppositely beyond the seat and locatedadjacent two opposite lateral sides of the second face of the base. 6.The heat dissipation device of claim 3, wherein each of the two heatpipes has one of the two second sections sandwiched between the secondface of the base and the seat, the other second section thereof locatedadjacent two opposite lateral sides of the second face of the base. 7.The heat dissipation device of claim 6, wherein the two heat pipes havethe first sections thereof extending beyond the seat and locatedadjacent another two opposite lateral sides of the second face of thebase.
 8. The heat dissipation device of claim 7, wherein the secondsections of the two heat pipes are parallel to each other.
 9. The heatdissipation device of claim 8, wherein one of the second sections of oneof the heat pipes is positioned between the two second sections of theother one of the heat pipes.
 10. The heat dissipation device of claim 2,wherein each of the two heat pipes is generally rectangular withoutbeing closed up and comprises four sections.
 11. The heat dissipationdevice of claim 10, wherein the two heat pipes are positioned in thesecond face of the base taking the format crossing loops, one of thefour sections of one of the heat pipes being positioned among the foursections of the other heat pipe.
 12. The heat dissipation device ofclaim 1, wherein the seat is located at a central portion of the secondface of the base.
 13. A heat dissipation device comprising: a seatadapted for absorbing heat from an electronic device; a base having afirst face and a second face opposite to the first face thermallycontacting the seat; a plurality of fins extending from the first faceof the base; and two heat pipes being thermally arranged on the secondface of the base, at least one of the two heat pipes being bent andhaving a section located adjacent to a center of the second face of thebase and engaged with the seat, and another section thereof locatedadjacent to a lateral side of the second face of the base and in noengagement with the seat.
 14. The heat dissipation device of claim 13,wherein both of the two heat pipes have a section located adjacent tothe center of the second face of the base and engaging with the seat,and another section located adjacent to a lateral side of the secondface of the base.
 15. The heat dissipation device of claim 14, whereineach of the two heat pipes is generally U-shaped, and comprises a firstsection and two second sections extending from two ends of the firstsection.
 16. The heat dissipation device of claim 14, wherein each ofthe two heat pipes is generally rectangular, and comprisesinterconnecting four sections.